JPH024896A - Load-resistant lubricating oil - Google Patents

Abstract

PURPOSE:To obtain the title lubricating oil suitable for hypoid gear oil for automobiles, industrial gear oil, worm gear oil, motor oil, turbine oil, hydraulic oil, etc., containing a base oil of lubricating oil and a specific amount of a specific hydroxyaryl fatty acid. CONSTITUTION:The aimed lubricating oil containing a base oil of lubricating oil and 0.005-25wt.% (preferably 0.1-5wt.%) hydroxyaryl fatty acid shown by the formula [R1 is 1-19C straight chain alkyl; R2 is 1-19C straight-chain alkylene (sum of C of R1 and R2 is 10-20); R3 and R4 are H, hydroxyl, 1-9C alkyl or alkoxy]. The lubricating oil has excellent oxidation stability and contains no elements such as S, Cl, P, etc., to cause corrosion and chemical wear.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention is applicable to hypoid gear oils for automobiles, industrial gear oils, worm gear oils, motor oils, various turbine oils, hydraulic oils, etc. under heavy load conditions. Regarding load-bearing lubricants.

[Conventional technology]

Mineral oil is mainly used as this type of industrial lubricant, but mineral oil alone cannot satisfy the lubricity under high loads, and to improve this, mineral oil is generally used to reduce friction and Contains additives to further reduce wear.

Fatty acids and esters are known as such additives, and typical examples include higher fatty acids such as oleic acid, higher fatty acid esters, sulfurized fats and oils, and chlorinated fats and oils.

[Problem to be solved by the invention]

However, in higher fatty acids and higher fatty acid esters, the longer the carbon chain length, the better the lubricity, but the higher the melting point, which is undesirable. For this reason, higher fatty acids having unsaturated bonds such as oleic acid are used as fatty acids, but fatty acids having such unsaturated bonds have the disadvantage that they are inherently susceptible to oxidation.

Further, sulfurized fats and oils and chlorinated fats and oils have excellent lubricity, but because they contain elements such as ions and chlorine, they are highly reactive with metals and may cause corrosion and chemical wear, which is not preferable. In addition, these additives may have a strong odor and may require a large amount of processing cost from the standpoint of environmental protection when disposed of after use, which is also economically unfavorable.

In view of the problems of the conventional lubricating oil additives mentioned above, the present invention can provide good lubricity, especially load resistance, has good oxidation stability despite being a liquid, and is corrosion resistant. The objective is to provide a load-bearing lubricant using lubricant additives that do not contain elements such as sulfur, chlorine, and phosphorous that cause chemical wear.

[Means to solve the problem]

As a result of intensive studies to achieve the above object, the present inventors found that certain hydroxyaryl fatty acids have good oxidation stability despite being liquid, and that they do not cause corrosion or chemical wear. Focusing on the fact that it does not contain elements such as sulfur, chlorine, and phosphorous, which is a good property as a lubricating oil additive, by adding a specific amount of this to the lubricating oil base oil, it can be used even under high loads. The present inventors have discovered that a high-performance lubricating oil with good lubricity, that is, excellent load resistance, can be obtained, and have completed the present invention.

That is, the present invention applies the following general 2; R, R together with the lubricating base oil.

(In the formula, R is a straight-chain alkyl group having 1 to 19 carbon atoms, R2
is a straight chain alkylene group having 1 to 19 carbon atoms, the sum of the carbon numbers of R and R2 is 10 to 20, and R1 and R4 are a hydrogen atom, a hydroxyl group, an alkyl group having 1 to 9 carbon atoms, or an alkoxy group. 0.05 to 25 hydroxyaryl fatty acids represented by
This relates to a load-bearing lubricating oil characterized by containing % by weight.

By the way, the above-mentioned hydroxyaryl fatty acid is liquid at room temperature and has excellent oxidation stability, and a technology that focuses on utilizing this property and its anti-rust and anti-corrosion effects is disclosed in US Patent No. 3,573.33
Disclosures can be found in the specification of No. 3 and Japanese Patent Application Laid-Open No. 61171799, and there is also a technique in which the above-mentioned hydroxyaryl fatty acid is induced into an ester and used as a lubricating oil to obtain a rust-preventing effect. This method has been proposed in JP-A-61-181895 and JP-A-62-199693.

However, as in the above-mentioned present invention, it is completely unknown that hydroxyaryl fatty acids themselves can be applied as additives to lubricant base oils, thereby achieving the high load-bearing properties described above. , was discovered for the first time through the efforts of the present inventors, and this point is a major feature of the present invention.

[Structure and operation of the invention]

The hydroxyaryl fatty acid used in the present invention is a hydroxyaryl fatty acid having a phenolic hydroxyl group in the molecule as shown in the above general formula, and is disclosed, for example, in JP-A-62-10040. It can be synthesized by the method described above, that is, by an addition reaction between an unsaturated fatty acid and a hydroxyaryl compound using activated clay and a phosphorus oxygen acid as a catalyst.

Specific examples of such hydroxyaryl fatty acids include hydroxyphenylmyristic acid, hydroxyphenylpalmitic acid, hydroxyphenylstearic acid, hydroxyphenylbehenic acid, bis-hydroxyphenylstearic acid, dihydroxyphenylmyristic acid, dihydroxyphenyl Palmitic acid, dihydroxyphenylstearic acid, trihydroxyphenylstearic acid, hydroxymethylphenylpalmitic acid, hydroxymethylphenylstearic acid, hydroxynonylphenylpalmitic acid, hydroxynonylphenylbehenic acid, hydroxymethoxyphenylstearic acid, hydroxymethoxyphenylbehenic acid Examples include henic acid.

In addition to the mineral oil hydrocarbons used in -a, the lubricating base oils used in the present invention include synthetic hydrocarbons such as alkylbenzenes and polyalphaolefins, synthetic lubricating oils such as polyether and ester oils, and natural lubricating oils. There are animal and vegetable oils and fats.

In the present invention, the above-mentioned hydroxyaryl fatty acid is blended into these lubricating oil base oils, and the content of this fatty acid in the entire lubricating oil should be in the range of 0.05 to 25% by weight, preferably 0.05 to 25% by weight. .1 to 5% by weight. If the content is less than 0.05% by weight, the desired good load-bearing properties cannot be obtained, and even if it exceeds 25% by weight, greater load-bearing properties cannot be expected, which is economically disadvantageous. .

In addition, the load-bearing lubricating oil containing the hydroxyaryl fatty acid of the present invention may contain commonly used antioxidants, viscosity index improvers, pour point depressants, rust inhibitors, anti-foaming agents, etc. as necessary. Various additives other than the hydroxyaryl fatty acids can be included.

〔Effect of the invention〕

As described above, in the present invention, by blending a specific hydroxyaryl fatty acid into the lubricant base oil,
It is possible to obtain high-performance lubricating oil with excellent load carrying capacity.
This lubricating oil includes automotive hypoid gear oil, industrial gear oil, worm gear oil, motor oil, various turbine oils,
It can be widely used as a lubricating oil used under heavy load conditions such as hydraulic oil.

〔Example〕

The present invention will be specifically explained below using examples. The names, raw materials, and analytical values of the hydroxyaryl fatty acids with symbols I to V used in the examples are shown in Table 1 below.

These hydroxyaryl fatty acids are disclosed in JP-A-62-100
It was synthesized according to the method described in Publication No. 40.

In Table 1, all raw fatty acids are from NOF ■, and the composition of commercially available oleic acid is 4% by weight of C14 monoene unsaturated fatty acids, 6% by weight of CI6 monoene unsaturated fatty acids, and 67% by weight of CI8 monoene unsaturated fatty acids. Weight%, C
The composition of commercially available high-purity oleic acid is 2% by weight of C4 monoene unsaturated fatty acid and 92% by weight of CI8 monoene unsaturated fatty acid, and the composition of commercially available erucic acid is 8% by weight of C2 monoene unsaturated fatty acid. Contains 88% by weight of unsaturated fatty acids.

Examples As shown in Table 2 below, various lubricant base oils and additives consisting of hydroxyaryl fatty acids with symbols I to E were combined, and the content of the additives was adjusted to the proportions listed in the table. Load-bearing lubricating oils of Samples 1'hl to 17 were prepared in the following manner.

Comparative Example As shown in the following Table 3, the lubricant base oil consists of a base oil alone, or additives other than hydroxyaryl fatty acids are added to the lubricant base oil so that the content thereof is in the proportions listed in the table. Alternatively, lubricating oil samples & 18 to 33 were prepared by adding hydroxyaryl fatty acids of symbols I to E to the lubricating oil base oil in a proportion such that the content thereof was less than 0.05% by weight as stated in the same table. .

In addition, in Tables 2 and 3, the commercially available mineral oil is 150 manufactured by Cosmo ■.
Neutral, commercially available polyalphaolefin is manufactured by Lion■ with a viscosity of 27 centistokes at 40°C, and commercially available alkylbenzene is manufactured by Matsuzoku Oil ■ with a viscosity of 1 at 40°C.
The commercially available polyether has a viscosity of 240 centistokes at 40°C, manufactured by Nippon Oil & Fats Corporation, and the commercially available DOA is dioctyl adipate, which has a viscosity of 8 centistokes at 40°C, manufactured by Nippon Rika ■.

Regarding each of the lubricating oils of samples m1 to m33 of the above Examples and Comparative Examples, a lubricating oil test was conducted in the following manner to evaluate their lubricating performance. The results were as shown in Tables 2 and 3.

<Lubricity Test> Using a Shell-type high-speed four-ball tester, the 1-minute fusion load, that is, the minimum load that causes fusion within 1 minute, was measured at a vertical rotation speed of 1.50 rpm.

As is clear from the results in Table 2.3 above, the lubricating oils of Samples 1 to 17 using the hydroxyaryl fatty acid of the present invention have oleic acid, which is currently widely used for improving lubricity. Sample parts 19 and 20 with additives
It can be seen that this lubricant exhibits much better load carrying capacity than the lubricating oil of

Furthermore, in the present invention, not only mineral oil-based hydrocarbons but also synthetic hydrocarbons, polyethers, ester oils, etc. are used as base oils, and by adding hydroxyaryl fatty acids, they all have good load resistance. It can also be seen that a sex lubricating oil can be obtained.

Patent applicant: NOF Corporation

Claims (1)

[Claims] (1) Along with the lubricant base oil, there are the following general formulas; ▲ Numerical formulas, chemical formulas, tables, etc. ▼ (In the formula, R_1 is a straight-chain alkyl group with 1 to 19 carbon atoms, R
_2 is a linear alkylene group having 1 to 19 carbon atoms, the sum of the carbon numbers of R_1 and R_2 is 10 to 20, and R_3 and R_4 are a hydrogen atom, a hydroxyl group, an alkyl group or an alkoxy group having 1 to 9 carbon atoms. 0.05 to 25 hydroxyaryl fatty acids represented by
A load-bearing lubricating oil characterized by containing % by weight.